1. Field of the Invention
The present invention relates to a device for controlling fail-safe of a hybrid vehicle and a method thereof. More particularly, the present invention relates to a device for controlling fail-safe of a hybrid vehicle, in which drive of an electric oil pump (EOP) is controlled with a voltage generated by a hybrid starter and generator (HSG) or a drive motor when a main relay is cut-off due to failure of a high voltage component, for providing fail-safe running of the hybrid vehicle, and a method thereof.
2. Description of Related Art
Although the hybrid vehicle may be different from a fuel cell vehicle and an electric vehicle in a narrow sense, in the specification, the hybrid vehicle is defined as a vehicle provided with one or more than one battery for using energy stored therein as driving power of the vehicle, including a general electric vehicle and a fuel cell vehicle.
The hybrid vehicle has an engine and a motor applied thereto as power sources, for displaying characteristics of the engine and the motor depending on a running situation to improve fuel consumption and reduce exhaust gas.
In general, the hybrid vehicle has an automatic transmission mounted thereto, and an mechanical oil pump (MOP), connected to and driven by a drive shaft of the engine, supplies oil to a low pressure part requiring lubrication and a high pressure part operating coupled elements in the automatic transmission.
Further, if operation of the engine stops, the mechanical oil pump also stops, to fail supply of the oil to the low pressure part and the high pressure part in an automatic transmission, causing decoupling of a friction element (clutch and brake) which maintains a first forward speed from a planetary gear.
In order to solve the foregoing problem, an electric oil pump driven by a voltage of a battery is mounted parallel with the mechanical oil pump additionally, for driving the electric oil pump (EOP) separate from the engine in the hybrid vehicle.
However, the mechanical oil pump has a disadvantage in that the mechanical oil pump, connected to the engine drive shaft, is normally driven when the engine maintains a start on state to cause a power loss thereby resulting in poor fuel consumption.
Accordingly, structures for omitting the mechanical oil pump from the hybrid vehicle and supplying the oil to the automatic transmission by a single drive of the electric oil pump have been developing.
Since the electric oil pump is driven by the voltage from the battery, if the main relay that connects/disconnects output of the battery voltage is opened due to failure of the high voltage component, the operation of the electric oil pump and the oil pump controller stops due to power supply cutoff.
Accordingly, since the oil cannot be supplied to the automatic transmission, shut down takes place in which the vehicle can run no longer.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.